Well the developer went out of buisness so they won't be making a second. Bethesda was only the publisher - it's certainly possible they'd publish a second CoC game but they don't have the license itself.
Hmm, with Call of Cthulhu being in the public domain, I'm sure any developer could pick up the reins and make the further adventures of Jack Walters and his Yithian masters. They put the kaibosh on Cthulhu and Dagon, perhaps they could do the same for Hastur or Shub-Niggurath.

Heck, Bethesda doesn't even have to publish.